Monitors Flashcards
What are the safety mechanisms of the ventilator?
- DISS/Pin system
- Oxygen supply failure alarm
- Fail safe valve (need oxygen to open the other valves
- Oxygen downstream (between patient and other gases)
- Linkage of oxygen nitrogen?
- Oxygen analyzer
How would you evaluate a patient preoperatively? Categories…
- History : records, allergies, medications
- Physical exam: airway, Neuro exam, heart, lungs, extremities (fluid status)
- Labs
- Imaging
How do you calculate how much oxygen you have left?
Oxygen cylinder pressure/ 200 X O2 L/min
What would you do if the central oxygen supply in the OR went out?
- Immediately switch to back up oxygen cylinders
- Disconnect the main pipeline supply so that the machine doesn’t still try to use this
- Hand ventilate at lower gas rates
- Ensure anesthesia - switch to TIVA, prepare for transport
- Get more e-cylinders
Would you use a PAC catheter?
I would not because of associated risks with placement and no evidence that it improves outcomes. However, I understand that some colleagues would use it to guide fluid management, help identify causes of hypotension, and provide means of pacing
How does oscillometric BP work?
Inflates until no pulsations (above systolic pressure)
Decreases pressure slowly until oscillations maximally increase (MAP)
A microprocessor derives systolic mean and diastolic pressures with an algorithm
How do pulse oximeters work?
It emits 2 different wavelengths of light, and then compares 2 wavelength absorptions and calculates the red/infrared ratio
Oxyhemoglobin absorbs more light at 960 mm, while deoxy absorbs more at 660 mm
In diastole, light is absorbed by tissue and blood
In systole, light is absorbed in the red and infrared bands
Why does methemoglobinemia cause a reading at 85%?
Because methemoglobin absorbs the same amount of light at the 2 wavelengths the LED emits, so there is a 1:1 absorption ratio of the red:infrared resulting in a reading of 85%
What are the advantages of an awake FO?
- Minimizing manipulation of the cervical spine
- Maintain spontaneous ventilation and avoid PPV that contribute to cardiopulmonary complications from increased intrathoracic pressure and decreased venous return
- Maintain airway reflexes, decrease aspiration risk
- Facilitate intubation and assess airways
What are the risks of placing a PAC?
Arrythmia Pulmonary infarction Pulmonary artery rupture Thrombosis Infection Errors in data interpretation
What are the risk associated with a wake up test?
Inadvertent extubation Intra op recall Pain Air embolism Dislodgement of IV lines
What are strategies to minimize blood loss?
Preop donation Acute normovolemic hemodilution Cell saver Deliberate hypotension Antifibrinolytics
How do you place an IO?
Place needle into the tibia at a 10 degree caudal angulation to avoid the epiphyseal plate and advance until there is a pop or loss of resistance. Check for free flow of fluids
What are some of the complications of an IO?
Compartment syndrome Extravasation Osteomyelitis Bacteremia Cellulitis Growth plate injury
Why would you order PFTs?
To obtain a diagnosis
Determine the severity of disease
Identify a reversible component
How does a TEG work?
Measures the viscoelastic properties of blood during induced clot formation
What are the discharge criteria for PACU?
Vital signs return to within 20% baseline
Pain and nausea control
Surgical hemostasis
Able to ambulate, no dizziness
What is the pulsatility index?
The ratio of the pulsatile blood flow to the non-pulsatile static blood flow
High correlation with capillary refill time
Indicator of reliability of the pulse oximeter
Also called perfusion index
How can pulsatility or perfusion index be used?
To ensure adequate epidural anesthesia (spike) due to peripheral vasodilation before onset
Detection of acute illness in an infant (will be low)
What is the normal range of PI?
.02-20%
This varies between monitoring sites and from patient to patient
What happens if you plug in Isoflurane to a sevoflurane vaporizer?
The delivered concentration will be higher than expected because the VP of Isoflurane is higher than that of sevo
How do vaporizers work?
They give a specific concentration calculated by the vapor pressure of the agent
What would you do if the line isolation monitor alarm went off?
Check the gauge to see if there is a true fault (reading over 5mA)
If so, unplug the faulty piece of equipment and remove/replace. Usually the last piece of equipment that is plugged in
What is the line isolation monitor for?
To monitor for macro shock
What conditions hinder accuracy of ST segment analysis?
LBBB WPW Acute pericarditis LVH with strain Digitalis Hypokalemia
